Explanation:
The tangential acceleration is given as 6.0 m/s². The radial (centripetal) acceleration is:
ac = v² / r
ac = (4.0 m/s)² / 20 m
ac = 0.80 m/s²
The total acceleration therefore has a magnitude of:
a² = at² + ac²
a² = (6.0 m/s²)² + (0.80 m/s²)²
a = 6.1 m/s²
And the direction (relative to the tangential direction) is:
θ = atan(ac / at)
θ = atan(0.80 m/s² / 6.0 m/s²)
θ = 7.6°
